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Fencer Vulns
critical 9.8

CVE-2017-12635 in the critical feed json

Due to differences in the Erlang-based JSON parser and JavaScript-based JSON parser, it is possible in Apache CouchDB before 1.7.0 and 2.x…

published 2017-11-14 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-4174

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
99.8%
EPSS 99.8% chance of exploitation in 30 days, percentile 99.9%
public exploits
4
Metasploit, Exploit-DB, plus a Nuclei check

Summary

Due to differences in the Erlang-based JSON parser and JavaScript-based JSON parser, it is possible in Apache CouchDB before 1.7.0 and 2.x before 2.1.1 to submit _users documents with duplicate keys for 'roles' used for access control within the database, including the special case '_admin' role, that denotes administrative users. In combination with CVE-2017-12636 (Remote Code Execution), this can be used to give non-admin users access to arbitrary shell commands on the server as the database system user. The JSON parser differences result in behaviour that if two 'roles' keys are available in the JSON, the second one will be used for authorising the document write, but the first 'roles' key is used for subsequent authorization for the newly created user. By design, users can not assign themselves roles. The vulnerability allows non-admin users to give themselves admin privileges.

Patch / fix

  • apache couchdb 1.7.0
  • couchdb Arch Linux 2.1.1-1

arch linux advisories AVG-495

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2017-12635 updated cvss 6.5

couchdb: Privilege escalation via _users documents with duplicate keys for 'roles'

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. First public exploit (Metasploit exploit/linux/http/apache_couchdb_cmd_exec)
  2. Published

Exploit prediction

99.84% chance of exploitation in the next 30 days, higher than 99.9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • Apache Software Foundation Apache CouchDB

Classification

Weakness
  • CWE-269 Improper Privilege Management

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.